(1) Field of the Invention
The invention relates to a tent roof construction with a flexible cover at least the portion forming the roof of which is defined by a three-dimensional metal or composite framework comprised of a frame module or a juxtaposition of several of these latter, each of which includes at least two parallel longitudinal beams, connected by means of cross beams, from which extend diagonal beams defining, as the case may be, two or more girders made integral by their top or even one or a series of pyramidally-shaped modules, within the inner space defined by such a frame module being understood to be at least one flexible cover of the type with a double curvature.
(2) Description of the Prior Art
Tent roof constructions that meet the above description are known already now. In fact, this kind of construction uses a metal frame formed of an assembly of profile bars defining, at least as regards the portion forming the roof, a three-dimensional framework inside which are subtended one or several cover elements made of a flexible material, usually of the type with a double curvature.
In fact, one should observe that hitherto such a three-dimensional metal framework uses metal profile bars of an elemental size that are connected to each other by means of connecting nodes, so as to define basic modules (such as described e.g. in DE 1170 6040) that are often in the shape of pyramids. Thus, several of these basic modules can be associated to each other, also by means of the above-mentioned nodes, to finally reach the roof size adapted to the construction. One should note that these often pyramidally shaped basic modules are, in addition, connected to each other by their top.
More in detail, a basic module includes two parallel longitudinal beams, which are furthermore connected to each other by means of crossbeams. With respect to these longitudinal beams extend diagonal beams that define either a pyramidal shape, these diagonal beams joining each other at the level of one and the same node, or two or more girders connected by their top.
One obviously understands that several of these modules can be juxtaposed so as to create a row, which has been defined as a frame module in the following description, it being understood that here too several of these frame modules can be associated to each other to reach the size wanted for the structure.
The problem that nowadays arises with this kind of construction tent roof including, as a roof, a three-dimensional metal framework resides in that their mounting time is particularly long, the more that lacing techniques are usually used for tensioning, at the level of such a framework, the cover elements made of a flexible material and with a double curvature. As a matter of fact, the tensioning of these cover elements most often occurs at the level of the connecting nodes.
On the basis of this finding, one obviously understands that these particular constructions are in no way adapted for a temporary use, since in particularly the mounting and dismantling operations prove particular expensive. Therefore, though they have a particular attractive aesthetic look, these constructions with a three-dimensional framework with subtended canvases with a double curvature find their usefulness only in the construction of buildings for permanent use, whereas for accommodating a temporary activity, there is no other solution than using more classical constructions.
These use, as the case may be, a substantially planar framework that, for forming the roof, receives one or several covers with a double curvature, in the shape of a Chinese hat, the tensioning of which often occurs from the inside. In this respect, it should be noticed that it is also known to tension these canvases with a double curvature from the outside of the building, by means of shrouds fixed to masts provided for this purpose.
As a matter of fact, one will more usually use tent roof constructions such as cornices or the like the structure of which is comprised of a series of gantries equidistantly connected to each other and formed of an assembly of profile bars with a groove for receiving, between two successive gantries, a cover element made of a flexible material the longitudinal edges of which are pre-provided with a retaining strip. This latter is thus capable of sliding inside the grooves of the above-mentioned profile bars.
One observes that both above-mentioned solutions used for the construction of buildings for temporary use give rise to the problem of their modularity. Thus, though this last-mentioned type of construction is more widely spread because it leads to a reduced mounting time, it is difficult to strictly adapt its shape or also its dimensions to the use it is intended for or even to the location reserved to it. The companies that offer this kind of construction for hire have indeed only a very small number of gantries of different sizes. In addition, when such a hiring company wants to be able to meet a large request from its customers, it must have in stock not only the elements, i.e. structures and covers, corresponding to the most used constructions, but also those for creating constructions of more particular sizes that are exceptionally requested by its customers. Hence, this gives rise to the problem of rotation of stock and thus of the profitability of these elements for constructions of special sizes.